Does semaphore guarantee the completion of load/store operation to shared memory?

I have a few questions about the mechanism of shared memory and semaphore,

1. Do all the load/store operations of shared memory "complete" before the semaphore releases ? Or just "issue" the operations, which means the value may changed after the semaphore releases ?

2. Are the load/store operations inside the code block protected by semaphore reordered during the execution?